The present invention relates to a method for addressing an electro-optical display device having a display comprising display elements which adjoin one another and are arranged in a row. The invention also relates to a drive circuit and a display device for carrying out the abovementioned method.
A method of the abovementioned type is known from the article by W. G. Freer, "Current Liquid Crystal Display Technology" in Microelectronics and Reliability, volume 15, pages 15-21, Pergamon Press 1976. With this method one display element which carries the data in a display device in which the individual display elements adjoin one another and are arranged in a row is supplied with in-phase voltage pulses and the other display elements are activated with out-of-phase voltage pulses so that a dark pointer-like display on a light background is produced. In particular, in the case of display devices with high resolution, the readability of display devices addressed in this way is, however, not adequate since the sole triggered element which carries the data is discernible only on looking very closely and in some cases can no longer be perceived at all from greater distances.
An improvement in the readability with the display device mentioned above can be achieved by triggering the upper or lower portion of the display elements arranged in a row as a bar display. However, this necessitates a relatively complicated addressing method.
An addressing method with which N strobe voltages are applied to the N row electrodes of display elements arranged in a matrix and M signal voltages are applied to the M column electrodes of these elements, these voltages having a value other than 0 only during the time interval t.sub.j =1/N.multidot.T, where T is the period of these voltages and j ranges through all the natural numbers .ltoreq. N is known from German Offenlegungsschrift No. 2,414,608. With this method one display element in each one of the M columns of the display elements arranged in a matrix is left dark on a light background. Since all of the selected display elements are rendered visible at the same time, this method is particularly suitable for the representation of single-valued graphs on plane surfaces.